BMW I Vision Dee – geometry retopo

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BMW I Vision Dee – geometry retopo

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Car retopo for toon character: bringing vital order into chaos

A futuristic concept car of the Bavarian car manufacturer had to be transformed into a cute cartoon character, bringing to mind the lovable protagonists of the feature film Cars. Although we were provided with a 3D-model of the car, like so often the case with this kind of products, the data was not up to the task of creating a rigged character.

Naturally the car designers use 3D software for their work as well and it stands to reason, that this data should be interchangeable in a way – which is true. The problem is, that they usually don’t build their models out of vertices and polygons, but with CAD-software (=description of the geometric forms with the aid of mathematical curves). You can export and transform this CAD-data into the polygonal data you need for rendering and if you don’t need deforming geometry, it’s not that big of a problem in most cases.

But as you can see in the examples below the exported underlying topology of the mesh is too inconsistent and chaotic to properly rig and animate a character without the risk of producing nasty artifacts and errors. The solution is retopology, which means building the object anew, but with a clean, evenly distributed mesh and taking care that all the while you are staying 100% identical with the original geometry.

Luckily Autodesk Maya provides a great tool-palette, specifically developed for this task. You can keep the original CAD-data as a snapable surface in the viewport and draw new four-sided polygons and whole rows of them directly on it. These tools greatly reduce the workload and make the task seem way less daunting!

With the now easily subdividable 3D-model of the car, the fantastic team at Aixsponza were able to produce a great character animation.